The Type 19 is a double triode intended to operate in Class B as a push-pull audio amplifier. The quiescent push-pull stage draws almost no current without an input signal and only draws high current on programme signal peaks. The aim was to reduce rate at which the expensive HT batteries were exhausted.
The 19 within a circle is very feint.
The twin triodes. The anodes are left bright as very little heat is generated.
A closer view.
The top mica. The filament tension springs attach to a central support.
The classic envelope is 38 mm in diameter, and excluding the UX6 base pins is 88 mm tall.
Reference: Data-sheet. Type 19 was first introduced in 1936. See also1936 adverts.
